This invention relates to methods of handling mushrooms, and in particular to the harvesting of mushrooms and the handling of those mushrooms immediately after the harvesting thereof. The invention further relates to apparatus for use in such handling methods.
Automated systems for the harvesting of mushrooms are known, but they tend to cause some damage to the mushrooms. Consequently, it is the usual practice to harvest by hand mushrooms intended for fresh retail sale, and mechanically-harvested mushrooms are usually used in the food processing industries, such as for soup or canning.
Manually harvested mushrooms are usually either cut by a picker from a growing bed, or may simply be pulled from the growing bed whereafter the stalk is cut to the required length. The mushrooms are then manually graded by size and are placed in appropriate packs or baskets by the picker. The full packs or baskets are collected and transferred to a cold store for cooling, for approximately 25 minutes, after which the packs are wrapped, usually by stretch-wrapping. The packs can then be dispatched direct to a wholesale or retail outlet, or may remain in the cold store awaiting dispatch
The shelf life of mushrooms harvested in the above manner for fresh retail sale is relatively short and is adversely affected by (a) the cutting of the stalk, (b) the amount of handling prior to cooling, (c) the time between picking and cooling and (d) the time taken fully to cool the mushrooms. In addition, apart from general deterioration of the mushrooms, these factors also affect the tendency of the mushrooms to discolour with time, and so be less attractive to the ultimate purchaser
Each retail outlet usually specifies the numbers of packs of mushrooms it requires day by day, the minimum weight of each pack and the grade (size) of the mushrooms in those packs. Unfortunately, growers cannot reliably have available for harvesting the required numbers of mushrooms of the required grade and this often leads to difficulties for the retail outlets in obtaining the supplies they believe their customers will require. In view of the very short shelf life of harvested mushrooms, attempts at storing the mushrooms until required for retail sale have not been very successful generally it is necessary for a mushroom farm to harvest, cut the stalks to the required length, cool, pack and dispatch the mushrooms to the wholesale or retail outlets all on the same day.
There are other problems associated with the known procedures in particular, the use of sharp knives for harvesting and/or stalk cutting is a growing concern, having regard to health and safety requirements in modern industries. The quality checking of full packs is not possible, for only the surface layer of the mushrooms can be checked visually. Moreover, the picker cannot select mushrooms to produce a pack of precisely the required weight; rather, the pack is filled until its weight exceeds some predetermined value but by then the actual weight in the pack may be significantly greater than the required weight In turn, this leads to considerable loss by the grower.
The present invention addresses the above problems, and in particular concerns the handling of the mushrooms at the time they are harvested In such a way that it is possible to store the mushrooms for longer than has otherwise been thought practical.
According to the present invention, there is provided method of handling mushrooms, comprising the steps of:
harvesting the mushrooms from a growing bed, leaving at least the greater part of the stalk still intact and connected to the cap;
depositing each harvested mushroom on a respective carrier therefor, which said carrier is configured to support the underside of the cap of the mushroom, with the stalk hanging free from the cap;
loading a plurality of mushrooms each supported as aforesaid into a compartment of a multi-compartmented storage structure arranged to allow the flow of air through the compartments thereof; and
moving the storage structure into a cold-room following the loading of at least some of the compartments of the structure with supported mushrooms, thereby to cool for storage all of the loaded supported mushrooms.
By using the method of the present invention, the handling of the mushrooms may be significantly reduced prior to the mushrooms being cooled. Moreover, since the stalk is left connected to the cap and is not shortened to the final required length for retail sale, the shelf life of the mushrooms is greatly extended. By employing the steps of this invention at the time of harvesting the mushrooms, the mushrooms may be stored for longer periods before significant deterioration takes place and only when the mushrooms are to be packed for retail sale, following a period of storage, are the stalks cut to the required length and the mushrooms graded for packing. In turn, this reduces the likelihood of the mushrooms exhibiting damage at the time of sale, as the mushrooms have been cooled before cutting and required handling for cutting is performed just before the mushrooms are packed for despatch, rather than prior to storage. These steps of cutting and packing may be performed on at least a semi-automatic, if not a wholly automatic, basis. This again reduces the time taken to perform the steps and also reduces the handling to which the mushrooms would otherwise be subjected.
In the handling method of the present invention, the time between the harvesting of the mushrooms and the cooling thereof can be greatly reduced, especially if the mushrooms are grown in trays containing the growing medium and the trays are then taken to the station at which the harvesting is performed. This may be contrasted with the conventional manual picking procedure where the picking operation is performed in a growing shed, and the stalk cutting and grading operations are also performed there. The mushrooms could however be grown in fixed beds, trays or aligned bags containing growing medium, and then picked either by hand or by an automated harvester which travels over the beds.
Though the mushrooms could be harvested by cutting the stalk with a sharp knife at or in the immediate vicinity of the surface of the growing bed, it is much preferred that each mushroom is harvested by substantially simultaneously twisting and pulling the cap away from the growing medium. In this way, the stalk may be left wholly intact, the lower end of the stalk breaking away from the mycelium in the growing medium.
It would be possible to provide an individual carrier for each mushroom. It is however far more efficient to provide a carrier adapted to support a plurality of mushrooms, with each mushroom separated from its neighbours. Conveniently, the carrier is in the form of an elongate strip appropriately configured to support at least one row, but preferably two rows, of mushrooms In the latter case, the strip may include appropriate recesses along its two long edges so that mushrooms may be located in the region of each recess and with the stalks of the mushrooms projecting downwardly through the recesses.
As the mushrooms are arranged on the carriers with the stalks substantially intact, it is likely that there will be some growing medium adhering to the stalks. In order to prevent that growing medium failing on other mushrooms also being stored in the storage structure, it is advantageous for the carrier to provide a wall portion below the bottom of the stalks of the carried mushrooms.
The storage structure may comprise a framework having members appropriately disposed to define a plurality of compartments, each compartment sized to receive a carrier together with the mushrooms supported thereby Thus, the storage structure conveniently may be in the form of a trolley defining a rectangular matrix of the compartments, to permit the storage structure easily to be moved from the station at which it is loaded with the carriers to a cold room for the cooling of the mushrooms.
The storage structure should allow the free flow of cool air through the various compartments, in order to facilitate the cooling of the mushrooms as quickly as possible down to the optimum storage temperature. Depending upon the configuration of the storage structure, that air flow may be transverse to the length of the carriers, or may be parallel thereto.
It will be appreciated that at least one of, but preferably both of, the loading and unloading of the mushrooms on and from the storage structure may be performed on an automatic basis using appropriate automated (robotic) apparatus. Such unloading apparatus as may be used should also be capable of placing the mushrooms in packaging therefor.
This invention extends to apparatus for use in the handling methods of the invention as described above. Thus, according to a second aspect of the present invention, there is provided apparatus for the storage of harvested mushrooms, which apparatus comprises a multi-compartmented storage structure having openings through the compartments to permit the free flow of air therethrough, in combination with a plurality of carriers for harvested mushrooms, each carrier being adapted to support the underside of a mushroom cap with the stalk projecting downwardly therefrom.
The storage structure may be in the form of an open framework of slats, rod-like or similar members. In the alternative, the storage structure may be constructed from sheet materials in either case, conventional engineering techniques may be employed to manufacture the structure, Conveniently, the structure is in the form of a wheeled trolley to permit the easy movement thereof, from place to place.
Each carrier may be in the form of a moulded plastics strip, provided with a plurality of U-shaped recesses each to receive a respective harvested mushroom The carrier may itself be of inverted channel shape, with the recesses formed in the base wall of the channel and the webs of the channel being cut away in order to provide lateral access to the recesses. In an alternative embodiment, the carrier may have upper and lower elongate strip-like walls held in a parallel and spaced apart disposition by a vertical web arranged centrally between the upper and lower walls. The upper wall may then be provided with U-shaped recesses along both long edges thereof, for receiving the mushrooms. The lower wall may serve as a base for the carrier and also to collect any growing medium or other debris adhering to the caps or the stalks of the mushrooms loaded onto the carrier. In order to assist retention of the mushrooms on this carrier, the upper wall may be slightly V-shaped, in order to encourage loaded mushrooms to move towards the vertical web.
In a further form of carrier of this invention, the mushrooms are supported on a plurality of elastic strips stretched between holders therefore, arranged along opposed upper edges of a channel-shaped member In this case, the base of the channel-shaped member may collect any growing medium falling from the mushrooms.